Scientists at an American biotechnology company achieved an important milestone in their quest for animal-to-human organ transplant: Creating piglets free of a retrovirus that has plagued advancement.

Researchers at Cambridge, Massachusetts-based eGenesis announced Thursday it raised the first animals, a litter of 37 piglets, free of PERVs — Active Porcine Endogenous Retrovirus.

The company seeks to use xenotransplantation, using animal organs for human transplant, as a way to "alleviate the severe shortage of organs for human transplantation." The company said nearly 118,000 people in the U.S. need a life-saving organ transplant and every 10 minutes someone is added to the waiting list.

But the fear of transmitting PERVs to humans was, among other hurdles, blocking progress toward successful xenotransplantation, making the eGenesis find an important one.

"This research represents an important advance in addressing safety concerns about cross-species viral transmission," said Luhan Yang, eGenesis' co-founder and chief scientific officer. "Our team will further engineer the PERV-free pig strain to deliver safe and effective xenotransplantation.”